*� Formatting of ModelChain.diode_params in pandas.DataFrame (#832)

Changes ModelChain.diode_params from tuple to DataFrame

Author: tylunel

docs/sphinx/source/whatsnew/v0.7.0.rst

@@ -19,6 +19,8 @@ API Breaking Changes
   of W/m2 rather than suns.
 * Calling :py:func:`pvlib.pvsystem.retrieve_sam` with no parameters will raise
   an exception instead of displaying a dialog.
+* The `modelchain.ModelChain.diode_params` attribute is now formatted in
+  a pandas.DataFrame with `DatetimeIndex`, rather than in a tuple.
 
 API Changes with Deprecations
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

pvlib/modelchain.py

@@ -8,6 +8,7 @@
 
 from functools import partial
 import warnings
+import pandas as pd
 
 from pvlib import (atmosphere, clearsky, pvsystem, solarposition, temperature,
                    tools)
@@ -453,9 +454,11 @@ def _singlediode(self, calcparams_model_function):
             calcparams_model_function(self.effective_irradiance,
                                       self.cell_temperature))
 
-        self.diode_params = (photocurrent, saturation_current,
-                             resistance_series,
-                             resistance_shunt, nNsVth)
+        self.diode_params = pd.DataFrame({'I_L': photocurrent,
+                                          'I_o': saturation_current,
+                                          'R_s': resistance_series,
+                                          'R_sh': resistance_shunt,
+                                          'nNsVth': nNsVth})
 
         self.dc = self.system.singlediode(
             photocurrent, saturation_current, resistance_series,
@@ -926,12 +929,11 @@ def run_model(self, weather, times=None):
         -------
         self
 
-        Notes
-        -----
         Assigns attributes: ``solar_position``, ``airmass``, ``irradiance``,
         ``total_irrad``, ``effective_irradiance``, ``weather``,
         ``cell_temperature``, ``aoi``, ``aoi_modifier``, ``spectral_modifier``,
-        ``dc``, ``ac``, ``losses``.
+        ``dc``, ``ac``, ``losses``,
+        ``diode_params`` (if dc_model is a single diode model)
         """
         if times is not None:
             warnings.warn('times keyword argument is deprecated and will be '